1. Field of the Invention
The invention relates to an image processing apparatus, an image processing method, and a computer program.
2. Description of the Related Art
Conventionally, printers interpret and analyze page description language (PDL) received from a network and carry out drawing to a main memory using cyan-magenta-yellow-black (CMYK) data generated based on the result of the analysis. In recent years, there is a growing demand for an increase in resolution and the speed of processing. To meet such a demand, a technology in which a part of the process that has been performed by a central processing unit (CPU) is carried out by other hardware is known. For example, Japanese Patent No. 4490783 discloses a printer having a built-in hardware circuit (a drawing device) that executes a drawing process on a controller board connected to a printer engine.
Here, a drawing device that performs drawing in units of band having a predetermined area is assumed to execute drawing on a band 2 indicated in FIG. 14. The drawing device reads out drawing commands stored in a main memory and executes a drawing process in accordance with the drawing commands read out. FIG. 15 is a diagram illustrating an example of the drawing commands. In this example, the drawing device first reads out a band initialization command and specifies the band 2 on which the drawing is performed. The drawing device then reads out a halftone pattern (1) set command and reads out a halftone pattern (an image after a halftone process is performed) for a band 1 from the main memory. The drawing device then reads out a rectangle (1) drawing command giving instructions to draw a rectangle (1) indicated in FIG. 14. However, because the rectangle (1) does not belong to the band 2, the drawing process is not performed.
The drawing device then reads out a halftone pattern (2) set command and reads out the halftone pattern for the band 2 from the main memory. Subsequently, the drawing device reads out a rectangle (2) drawing command giving instructions to draw a rectangle (2) indicated in FIG. 14 and executes a drawing process of the rectangle (2). The drawing device then reads out a halftone pattern (3) set command and reads out the halftone pattern for a band 3 from the main memory. Then, the drawing device reads out a rectangle (3) drawing command for giving instructions to draw a rectangle (3) in FIG. 14. However, because the rectangle (3) does not belong to the band 2, the drawing process is not performed. The drawing device reads out a band end command thereafter and finishes the drawing process for the band 2.
In the above-described example, the drawing device reads out the halftone pattern each time the halftone pattern set command is read out, which makes it difficult to increase the speed of processing until drawing is completed.
There is a need to provide an image processing apparatus, an image processing method, and a computer program product that can achieve an increase in the speed of processing until drawing is completed.